NativeScript Nodeify

Makes most npm packages compatible with NativeScript

Q & A

Q. WTF?

A. Good question, glad you asked! You can't just use any npm package with NativeScript as they may depend on built-in Node modules (fs, path, crypto to name but a few). Those modules aren't plain old JavaScript files so they can't be executed in the {N} runtimes.

Q. So how does this plugin overcome that situation?

A. You can install dependencies as normal, and this plugin as well, then at build time a hook installed by this plugin will scan and modify your npm modules (in the platforms folder) as it sees fit to make them {N}-compatible.

Q. Lol. Wut? Modify my precious modules!?

A. Yes. The hook looks at the packages installed in <app>/platforms/<ios|android>/.../tns_modules and for each dependency it does a few things:

• Look for a browser node in their package.json and find-replaces any matching require() calls in that package and its dependencies.
• If there's a main replacement in the browser node it also takes care of that.
• If any of the dependencies (and this can go deeeeeeeeeeep - remember left-pad?) contains something we need to shim, we will based on this list.
• There's more trickery and there may be more needed, so this list is a bit evolving atm..

Q. But doesn't browserify / Webpack solve this for us?

A. Not in this case, at least not without further modifications. Think modules that don't have a browser node in their package.json, or modules that do but shim their node dependency with something that needs a real browser.. Feel free to submit a PR for a nicer implementation, but this is the best I could think of.

Q. Not bad actually, but doesn't come with a performance hit?

A. Thanks. And good question. Most importantly, at runtime this should make no difference as you're not 'requiring' more that you were already, just different implementations (that actually work, I hope). A build time you will see a few seconds added to your build (but it shouldn't affect livesync). The hook skips checking tns-core-modules and anything starting with nativescript.

Installation

From the command prompt go to your app's root folder and execute:

tns plugin add nativescript-nodeify

Usage

Include this in your code before requiring the problematic npm module.

require("nativescript-nodeify");

Demo app

The demo tests a few popular libraries that depend on Node built-in modules which would normally not work in a NativeScript runtime environment.

Run the demo app from the root of the project: npm run demo.ios or npm run demo.android.

Know issues

This plugin isn't perfect, but it tried to solve issues for as many of the gazillion npm packages out there. A few issues are known, if yours is not in this list please create an issue.

• Like Browserify we're using shims to fill the gaps between Node and the browser, but unlike Browserify shims we're not running in a browser, so some API's may not be available. Anything that touches the DOM for instance.
• The http shim isn't perfect (like usage of global.location.protocol.search), so may need to do what RN did and roll our own (if anyone needs it).

Recipies

To get you started with a few popular npm modules, here's some recipies. Please share your own by sending a PR to this repo!

All recipies assume you've already done:

$ tns create awssdk
$ cd awssdk
$ tns platform add ios
$ tns platform add android
$ tns plugin add nativescript-nodeify

node-uuid

$ npm install node-uuid --save

Boom! Done.

jsonwebtoken

$ npm install jsonwebtoken --save

Boom! Done. Again.

aws-sdk or amazon-cognito-identity-js (which includes aws-sdk)

This one requires a bit more setup, but it's not too bad:

Never check in your AWS keys! Bots scan public repos and will create server instances you'll get billed for.

Depending on what you need:

$ npm install aws-sdk --save

or

$ npm install amazon-cognito-identity-js --save

To parse XML returned from AWS correctly (fi. when listing S3 bucket contents) we need to patch an additional library because the browser shim expects an.. ehm.. browser.

So open you app's package.json and add this nodeify node to the existing nativescript node:

{
  "nativescript": {
    "nodeify": {
      "package-dependencies": {
        "aws-sdk": [
          {
            "xml/browser_parser": "xml/node_parser",
            "lib/node_loader": "lib/browser_loader"
          }
        ]
      }
    }
  }
}

Then in your code for amazon-cognito-identity-js:

// require this to fix an issue with xhr event states
require('nativescript-nodeify');

// register a user (here's a bit, but see the demo and https://github.com/aws/amazon-cognito-identity-js for details)
var AmazonCognitoIdentity = require('amazon-cognito-identity-js');
var CognitoUserPool = AmazonCognitoIdentity.CognitoUserPool;
var userPool = new CognitoUserPool({UserPoolId: 'foo', ClientId: 'bar'});

Now just use AWS as usual:

// then require AWS and interact with s3, dynamo, whatnot
var AWS = require('aws');